Author: markt
Date: Wed Mar 3 22:18:01 2010
New Revision: 918737
URL: http://svn.apache.org/viewvc?rev=918737&view=rev
Log:
Align comments and whitespace between the two JvmRouteBinderValve
implementations.
No functional change.
Modified:
tomcat/tc5.5.x/trunk/container/modules/ha/src/share/org/apache/catalina/ha/session/JvmRouteBinderValve.java
Modified:
tomcat/tc5.5.x/trunk/container/modules/ha/src/share/org/apache/catalina/ha/session/JvmRouteBinderValve.java
URL:
http://svn.apache.org/viewvc/tomcat/tc5.5.x/trunk/container/modules/ha/src/share/org/apache/catalina/ha/session/JvmRouteBinderValve.java?rev=918737&r1=918736&r2=918737&view=diff
==============================================================================
---
tomcat/tc5.5.x/trunk/container/modules/ha/src/share/org/apache/catalina/ha/session/JvmRouteBinderValve.java
(original)
+++
tomcat/tc5.5.x/trunk/container/modules/ha/src/share/org/apache/catalina/ha/session/JvmRouteBinderValve.java
Wed Mar 3 22:18:01 2010
@@ -45,40 +45,51 @@
/**
* Valve to handle Tomcat jvmRoute takeover using mod_jk module after node
- * failure. After a node crashed the next request going to other cluster node.
- * Now the answering from apache is slower ( make some error handshaking. Very
- * bad with apache at my windows.). We rewrite now the cookie jsessionid
- * information to the backup cluster node. After the next response all client
- * request goes direct to the backup node. The change sessionid send also to
all
- * other cluster nodes. Well, now the session stickyness work directly to the
- * backup node and traffic don't go back too restarted cluster nodes!
+ * failure. After a node crashes, subsequent requests go to other cluster
nodes.
+ * That incurs a drop in performance. When this Valve is enabled on a backup
+ * node and sees a request, which was intended for another (thus failed) node,
+ * it will rewrite the cookie jsessionid information to use the route to this
+ * backup cluster node, that answered the request. After the response is
+ * delivered to the client, all subsequent client requests will go directly to
+ * the backup node. The change of sessionid is also sent to all other cluster
+ * nodes. After all that, the session stickyness will work directly to the
+ * backup node and the traffic will not go back to the failed node after it is
+ * restarted!
*
- * At all cluster node you must configure the as ClusterListener since 5.5.10
- * {...@link org.apache.catalina.ha.session.JvmRouteSessionIDBinderListener
JvmRouteSessionIDBinderListener}
- * or before with
- * org.apache.catalina.ha.session.JvmRouteSessionIDBinderListenerLifecycle.
+ * <p>
+ * For this valve to function correctly, so that all nodes of the cluster
+ * receive the sessionid change notifications that it generates, the following
+ * ClusterListener MUST be configured at all nodes of the cluster:
+ * {...@link
org.apache.catalina.cluster.session.JvmRouteSessionIDBinderListener
+ * JvmRouteSessionIDBinderListener} since Tomcat 5.5.10, and both
+ * JvmRouteSessionIDBinderListener and JvmRouteSessionIDBinderLifecycleListener
+ * for earlier versions of Tomcat.
*
+ * <p>
* Add this Valve to your host definition at conf/server.xml .
*
* Since 5.5.10 as direct cluster valve:<br/>
+ *
* <pre>
* <Cluster>
* <Valve
className="org.apache.catalina.ha.session.JvmRouteBinderValve" />
* </Cluster>
* </pre>
+ *
* <br />
* Before 5.5.10 as Host element:<br/>
* <pre>
- * <Hostr>
+ * <Host>
* <Valve
className="org.apache.catalina.ha.session.JvmRouteBinderValve" />
- * </Hostr>
+ * </Host>
* </pre>
*
- * Trick:<br/>
- * You can enable this mod_jk turnover mode via JMX before you drop a node to
all backup nodes!
- * Set enable true on all JvmRouteBinderValve backups, disable worker at
mod_jk
- * and then drop node and restart it! Then enable mod_jk Worker and disable
JvmRouteBinderValves again.
- * This use case means that only requested session are migrated.
+ * <em>A Trick:</em><br/>
+ * You can enable this mod_jk turnover mode via JMX before you drop a node to
+ * all backup nodes! Set enable true on all JvmRouteBinderValve backups,
disable
+ * worker at mod_jk and then drop node and restart it! Then enable mod_jk
worker
+ * and disable JvmRouteBinderValves again. This use case means that only
+ * requested sessions are migrated.
*
* @author Peter Rossbach
* @version $Revision$ $Date$
@@ -369,8 +380,7 @@
sendSessionIDClusterBackup(manager,request,sessionId,
newSessionID);
}
- lifecycle
- .fireLifecycleEvent("After session migration",
catalinaSession);
+ lifecycle.fireLifecycleEvent("After session migration",
catalinaSession);
if (log.isDebugEnabled()) {
log.debug(sm.getString("jvmRoute.changeSession", sessionId,
newSessionID));
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